Loop-retainer for sewing-machines.



H. J. DAHL.

LOOP RETAINER FOR SEWING MACHINES.

APPLICATION FILED JAN-17. 191s.

WITNESS JWw IIVVE/VTOR Hamil Zia/$4.

"UNTTE @TTES PATEN FFTE.

HARRY J". DAI-IL, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR IO LUCIUS N. LITTAUER, OF GLOVERSVILLE, NEW YORK.

LOOP-RETAINER FOB SEWING-MACHINES.

Spe cifieation of Letters Patent.

Patented May as, 1917.

Application filed January 17, 1916. Serial No. 72,378.

To all whom it may concern.

Be it known that I, HARRY J. DAHL, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented :ertain new and useful Improvements in Loop-Retainers for Sewing-Machines, of which the following is a specification.

This invention relates to sewing machines, and more particularly to loop retainer mechanism therefor, the object of the invention being to provide an improved mechanism for controlling the needle loop' while such loop is on the looper.

Another object of the invention is the provision of improved means operative into and out of the path of the looper at the top edge thereof so as to hold the'needle loop to one side of the line of reciprocation of the needle and thus keep the needle loops out of the path of the needle while it is descending and co-acting with the looper, and entering between the looper thread and the looper body in the formation of a twothread double-chain Zlg-Zfifl stitch.

A further object of the invention is the provision of an improved looper retainer simple in construction and in its number of parts and effective in use, and which may be conveniently located without interfering with the other mechanisms of the machine or the adjustments thereof, and which may be readily attached to ordinary machines without alteration of its standard parts.

While the invention is especially useful in connection with zig-zap; stitching mechaaism, it is by no means confined thereto. as it may he useful. in other forms'of stitching mechanisms, and therefore the various details may be more or less modified without departing; from the scope of this invention.

In the drawings accompanying and forn ing part of this specification, Figure 1 is a top plan view of'the forward end of a sewinn machine of the type known. as a Metropolitan sewing: machine, showing the looper and loop retainer mechanism, certain parts being broken away to more clearly show the several parts; Fig. 2 is a sectional view of Fig. 1, taken on the line '22,-looking in the direction of the arrow, Fig. 1, and shows the position of the looper and feeding mechanism; Figs. 3, 4t, 5 and 6 are details showg t e per 10 p retainer, need e a d needle guards in different positions, and illustrating the manner in which the loop retainer co-acts with the looper and needle thread in the formation of the stitch; Fig. 7 is a front view showing the loop retainer and looper mechanism; Fig. 8 is an end view of Fig. 7 looking; in the direction of the arrow, Fig. 7, and shows the co-aetion of the cam carried by the end of the main shaft, the loop retainer actuator and the spring and plunger that keeps the same in working position against the cam; and Fig. 9 is a, detail perspective View of the loop retainer and its connecting parts.

Similar characters of reference indicate corresponding: 1. rrts in the different figures of the drawings.

The base or bed plate 1 of the machine carries he main driving shaft 2, on which the looper vibrating eccentric 3 is secured. This eccentric operates in the yoke 4, which is thus reciprocated at right angles to the shaft 2 by the eccentric 3. This yoke has a bearing to receive the reduced end of the looper shaft 6. A collar 7, a shoulder 8 and nuts 9 limit the endwise play of this shaft. Thus it will have endwise reciprocating movement,-lmt no end play in its bearing 5. This shaft 6 extends forward through bearings 10 of the looper bracket and reciprocates therein. A looper rocker 11 oscillates on the shaft between the bear ings 10 at right angles to the looper shaft. The looper 12 is pivotally secured to the looper rocker 11. but projects through an elongated slot 13 in the loop-er rocker, and has its circular end 1% fitting into a slot in the looper shaft 6. and this looper has an extending; stem 15. The needle guard 16 is secured to the looper, as at 17, and has its forward end slightly curved, as at 18, to properly cooperate with the needle 19. The looper is provided with the usual thread carrying? blade 20 having a thread groove 21 and a thread eye 22 in the rear thereof, and a thread eye 23 in the front needle loop engaging end. The top of the looper at its forward or loop taking end is curved in the are of a circle concentric with the aXis of Ell ' center of the blade.

the top edge of the looper. This construction of the looper enables the loop retaining finger to operate close to the looper, so close in fact, that the thread will be prevented from passing between the loop retainer and the looper in case it should slip off of the loop retainer. The top of the looper is provided with a recess 24 for the passage of the loop retainer. In the average sewing machine, where a loop retainer is used, it is not necessary thatthe top of the looper at its forward end be curved in the manner just described. In fact, it is often higher at the point and sometimes in the This looper is oscillated in one direction by the rod 26 pivotally secured to the looper rocker 11 by the screw 27, and in a transverse direction or sidewise by the reciprocating movement of theshaft 6. Another needle guard 28 is adjustably secured. to an angle bracket 29 of the looper rocker or driver, and its adjusting'means, indicated by 30, Fig. 7, is effective to position the same relative to the needle. To distinguish the two needle guards this one may be termed a back needle guard, while the guard 16 attached to the looper may le termed a front needle guard. It will be understood that the back needle guard merely has a movement in one direction because it is attached to the looper rocker 11, while the needle guard 16 travels with the looper and moves in several directions, having four motions, that is to say it has a fixed position relatively to the looper blade, while the guard 28 has a variable relation relatively to the blade because the looper rocks toward and from it in going around the needle.

The feeding mechanism as well as certain features of the looper mechanism are of the well known Metropolitan construction, and this feeding mechanism briefly consists of a rocker frame 31 pivoted to the machine base, as at 32. A feed bar 33 is pivotally secured to this rocker frame, as at 34, and carries a feed dog 35 and has a feed lift eccentric strap 36 connected therewith, as at 37, to give the rising and falling movement to the feed dog. A pitman 38 is also connected with the rocker frame shaft 34 and is oper ated by an adjustable crank 40 for regulating the throw of the feed, and the main driving shaft 2 carries a disk 41 which opers ates this crank 40. Secured to the periphery of this disk 41 by a screw 43 is a cam 42. This cam is so shaped, as at 44, Fig. 8, that it will impart movement to a member 45 which forms with the parts 46 and 47 a crank which is pivotally supported in a cut out portion 48 of a bracket 49 secured to the front wall 50 of the machine base 1. An adjustment of bracket 49 is provided by means of screws 51 passing through the elongated slots52 where it is attached to the front wall 50, thereby to fix the position of the member 45 with respect to the cam 42. The member 45 has an extending end 53 to act as a stop against the bracket 49, as at 54, to limit its movement in one direction. Attached to the bracket 49, (see Figs. 7 and 8) is an angle piece 5-5 bored to receive a coiled spring 56 and a plug 57. The spring forces the plug against the member 45 and holds it against the cam 42 so that it will positively follow the periphery of the cam 44 when this is rotated. at high speed and without noise. The part 47 is in the form of a vertical pivot, and an arm 59 is secured to the top thereof and this arm is bored to receive the stem of the loop retainer 61. This loop retainer extends outwardly and upwardly and is so shaped as to clear the feeding mechanism and other parts. The loop engaging end of the loop retainer is substantially tri angular in'a direction transverse tov its direction of movement and thus has a straight side 64 and a curved side 65 forming a point 63 projecting transversely of the curved stem of the loop retainer; The purpose of the curved edge of this loop retainer is to insure a quick shedding action of the loop and overcome the drag on the thread, which shedding action would not be as effectively accomplished if the loop retainer were made simply with a point and therefore with slight inclination. The straight side is essential in order to bring the loop retainer to a point in connection with the curved side and to clear the other moving parts of the machine. The curved side of the loop retainer prevents the loop from hanging on to thepoint and affords a more positive means of quick release for the loop instantly as'the retainer moves away from the looper. t is essential that the action of the loop retainer in its cooperation with-the looper be such that its point enter the loop just sufficient to hold it to one side of the path of the needle until the needle has entered the looper loop, at which time the retainer quickly recedes to cast off the needle loop, and this shedding of the needle loop must be quick so to overcome any drag on the thread and the particular form of the loop retainer shown accomplishes these results in a very advantageous way. In viewing 1, 7 and 8 it will be seen that the loop retainer mechanism is not only located conveniently to permit the necessary adjustments, but is out of the way of the other operating mechanisms, and that it is very simple in construction, consisting of but few parts, so that it can be readily applied to any machine without altering the standard parts thereof.

This improved loop retainer operates as follows: The needle is reciprocated and vibrated so as to deliver a loop of the needle thread to the l p r in a right hand p0sition, at which time the looper and the loop retainer are in the position shown in Fig. 3. The looper enters the needle loop 66 as the needle is rising, then it vibrates say to the left, and as the needle starts to descend the main shaft actuates the looper and rocks it so that the looper blade 20 moves to a position in front of the needle. At the same time the cam 42 is turned to bring the part 4A into position to cooperate with the crank member i5 and so turn the pivot 47 and swing the arm 59 and the finger 61 so that the point 63 of the loop retainer passes in over the top of the looper as shown in Fig. 4, at which time the needle loop 66 is drawn to the right of the needle so that the retainer point 63 may pass to the left of the needle loop 66 and hold said loop against move ment toward the needle while the looper is moving out of the needle loop in the direction of the arrow shmvn. in Fig. 4-. The pull of the looper thread 67 tends to cause the needle loop 66 to move toward the needle at this position in the formation of the stitch, and the loop retainer is for the purpose of preventing such movement and to overcome the possibility of the loop 66 moving on the looper to a position underneath the needle, in which case the needle would enter in between the strands of the loop 66 and interfere with the proper formation of the stitch and the drawing up of the loops into the work. This is more likely to occur in Zigzag machines because of the vibration of the needle when it moves from the left to the right hand line of reciprocation, because of the ends 68 of the needle loops being joined to the preceding stitch at the left position of the needle reciprocation. That is to say, there is more drag to the left by the needle loop which is made at the time the needle mores from the left-hand position to the right-hand position. The object of the loop retainer isto have its movement such as to the top of the looper blade while the needle 66 is held to the right and thus retain the loop until the needle has again descended and its point has passed between the back of the looper blade and the strand of looper thread indicated by 89, (see Figs. 5 and 6). Instantly, when the needle is sufficiently past the looper thread, the point of the retainer is withdrawn from the loop in the direction indicated by the arrows in Figs. 5 and 6, thus permitting the loop 66 to cast off from the looper blade 20 and draw up tightly to the work.

From the foregoing it will be seen that the movement of the loop retainer is such iatit swings over the looper and holds the ;-eedle loop while the needle is descending, and hat instantly as the needle point has secured the loop of looper thread, the retainer is withdrawn to its initial position, and hence the periphery of the cam 4&2 is con centric except for a small portion 44 representing but a few degrees of a circle, and that the top of this projection ts is a gradual, easy curve, so that in operating the parts run quietly and are capable of high speed without undue wear or noise.

Furthermore, a cam motion is more desirable than an eccentric or crank motion, be cause a quick movement is necessary to control the needle loops and move its loop re tainer instantly out of position so as to hold the needle loop as short a time as possible, since this permits sewing at higher speed and the drawing up of a tight, uniform stitch with a minimum of tension on the threads.

I claim as my invention:

1. in a sewing machine having looper mechanism, the combination of loop retaining means comprising a loop retainer shiftable across the top of the looper and having substantially a triangular formation transversely of its direction of movement and forming a loop engaging point, and means for actuating said loop retaining means.

2. In a sewing machine having looper mechanism, the combination of loop retaining means comprising a loop retainer shiftable across the top of the looper and having substantially a triangular formation transversely of its direction of movement and forming a loop engaging point, a driving shaft, and means mounted thereon for actuating said loop retaining means.

3. In a sewing machine having looper mechanism, the combination of loop retaining means comprising a loop retainer shiftable across the top of the looper and having substantially a triangular formation transversely of its direction of movement and forming a loop engaging point, a driving shaft, and cam mechanism mounted thereon for actuating said loop retaining means.

Al. In a sewing machine having looper mechanism, the combination of loop retain ing means comprising a loop retainer shiftable across the top of the looper, a driving shaft, means mounted thereon for actuating said loop retaining means and comprising cam mechanism, and spring actuated means connected ith said loop retaining means for cooperating with the cam.

in a sewing machine having looper mechanism, the combination of loop retaining means comprising a loop retainer shiftable across the top of the looper and having a point, a curved edge and a straight side both merging into said point, a driving shaft, means mounted thereon for actuating said loop retaining means and comprising cam mechanism, and spring actuated means connected with said loop retaining means for cooperating with the cam.

6. In a sewing machine having looper mechanism including a looper having a recess in the top thereof, the combination of loop retaining means'including a loop retainer having substantially a triangular formation transversely of its direction of movement and movable across the top of the looper adjacent to its recess, and means for operating said loop retaining means.

7. In a sewing machine the combination of looper mechanism including a looper and a looper shaft, said looper having the top of the forward end thereof curved in the arc of a circle concentric with the axis of the looper and having. its top provided with a recess, loop retaining means including a loop retainer cooperating with said looper adjacent to said recess, and means for swinging said loop retaining means across the top of the looper.

8. In a :sewing machine, the combination of looper mechanism including a looper hav ing a in the top thereof, loop retaining means including a loop retainer cooperating with said looper adjacent to said recess, and means for swinging said loop retainer across the top of the looper and comprising a cam and spring actuated means connected with the loop retainer and cooperating with said 021111.,

9. In a sewing machine, the combination of looper mechanism comprising a looper having a recess in the top thereof, a driving shaft, a cam mounted thereon, a loop retainer operative across the top of the looper adjacent to said recess, a crank connected with said loop retainer, and spring actuated means'for maintaining a part of said crank in engagement with the cam.

10. In a sewing machine the combination of a loop retaining mechanism comprising a loop retainer having substantially a triangular formation transversely of its direction of movement, and means for swinging it into and out of itsoperative position.

11. In a sewing machine the combination of loop retaining mechanism comprising a loop retainer having substantially a triangular formation in a direction transverse to its direction of movement and forming a loop engaging point having a curved side and a straight side, and means for swinging it into and out of its operative position and comprising cam mechanism.

12.- In a sewing machine, the combination of a loop retaining mechanism comprising a loop retainer having a pointed end, a curved side and a straight side, means for swinging it into and out of operation and comprising cam mechanism, a crank connected with said loop retainer and adapted to be engaged by the cam, and spring actuated means for maintaining said crank in engagement with said cam.

13. In a sewing machine, the combination of looper mechanism comprising a looper and a looper rocker, means for actuatingv the looper and its rocker loop retaining means, and a pair of needle guards one carried by the looper and the other by the looper rocker.

14. In a sewing machine, the combination of looper mechanism comprising a looper and a looper rocker, means for actuating the looper and its rocker, loop retaining means, and a pair of needle guards one carried by the looper and the other by the looper rocker, one having a fixed position relatively to the looper and the other a variable position relatively to the looper.

15. In a sewing machine, the combination of looper mechanism comprising a looper and a looper rocker, meansfor actuating the looper and its rocker, loop retaining means, a pair of needle guards one carried by the looper and the other by the looper rocker, one having a fixed position relatively to the looper and the other a variable position relatively to the looper, and cam operated means for operating said loop retaining means.

16. In a scwin g machine, the combination of a driving shaft, looper mechanism including a looper and a rocker operatively connected with said driving shaft, loop retaining means connected with the driving shaft, and a pair of needle guards one attached to the looper and movable therewith andthe other with the looper rocker.

17. In a sewing machine having looper mechanism comprising a looper and a looper rocker, the combination of a pair of needle guards one attached to the looper and the other connected with the looper rocker, and means for actuating said looper and its rocker.

18. In a sewing machine, the combination of looper mechanism comprising a looper, a looper rocker connected with said looper, means for shifting the looper in one direction, and means for shifting the looper rocker and its looper in a transverse direc tion, a pair of needle guards one carried by the looper and the other by the looper rocker whereby one is fixed relatively to the looper while the other is movable relatively thereto.

19. In a sewing machine, the combination of looper mechanism comprising a looper, a looper rocker connected with said looper, means for shifting the looper in one direction, means for shifting the looper rocker and its looper in a transverse direction, a pair of needle guards one carried by the looper and the other by the looper rocker whereby one is fixed relatively to the looper while the other is movable relatively thereto, and loop retaining means cooperating with the looper.

20. In a sewing machine, the combination of looper mechanism comprising a looper, a looper rocker connected with said looper, means for shifting the looper in one direction, means for shifting the looper rocker and its looper in a transverse direction, a pair of needle guards one carried by the looper and the other by the looper rocker whereby one is fixed relatively to the looper while the other is movable relatively thereto, and loop retaining means cooperating with the looper and operative to engage the loop between said needle guards.

21. In a sewing machine, the combination of looper mechanism comprising a looper, a looper rocker connected with said looper, means for shifting the looper in one direction, means for shifting the looper rocker and its looper in a transverse direction, a pair of needle guards one carried by the looper and the other by the looper rocker whereby one is fixed relatively to the looper while the other is movable relatively thereto, and loop retaining means cooperating with the looper and operative to engage the loop between said needle guards and above the top of one of them.

22. In a sewing machine, the combination of looper mechanism comprising a looper, a looper rocker connected with said looper, means for shifting the looper in one direction, means for shifting the looper rocker and its looper in a transverse direction, a pair of needle guards one carried by the looper and the other by the looper rocker whereby one is fixed relatively to the looper while the other is movable relatively thereto, and loop retaining means cooperating with the looper and operative to engage the loop between said needle guards and above the top of one of them and across the top of the looper.

23. In a sewing machine the combination of looper mechanism including a looper and means for actuating it, a looper retainer having a loop engaging end and pivotally supported for swinging movement in a hor1- zontal plane transversely of the main direction of movement of the looper, and means for swinging it.

24:. In a sewing machine the combination of looper mechanism including a looper and means for actuating it, a loop retainer having a loop engaging end and pivotally supported away from and in front of the loop engaging end of the looper for swinging movement in a horizontal plane transversely of the main direction of movement of the looper, and means for swinging it.

25. In a sewing machine the combination of looper mechanism including a looper and means for actuating it, a loop retainer having a loop engaging end and pivotally supported away from and in front of the loop engaging end of the looper for swinging movement in a horizontal plane transversely of the main direction of movement of the looper, and a cam for swinging it.

9.6. In a sewing machine the combination of looper mechanism including a looper and means for actuating it, a loop retainer having a loop engaging end and a stem eX- tending therefrom in a'direction away from and in front of the loop engaging end of the looper and pivotally supported to permit its loop engaging end to swing transversely of the main direction of movement of the looper, and means for swinging said loop retainer.

27. In a sewing machine the combination of looper mechanism including a looper and means for actuating it, a loop retainer having aloop engaging end and a stem extending therefrom in a direction away from and in front of the loop engaging end of the looper and pivotally supported to permit its loop engaging end to swing transversely of the main direction of movement of the looper, and a cam for swinging said loop retainer.

28. In a sewing machine the combination of looper mechanism including a looper and means for actuating it, a loop retainer havin a loop engaging end and a stem extending therefrom in a direction away from and in front of the loop engaging end of the looper and pivotally supported to permit its loop engaging end to swing transversely of the main direction of movement of the looper, and a cam for swinging said loop retainer, said cam having a concentric face throughout the major part thereof and an eccentric face for a small part thereof having gradual easy curve unitin such faces.

29. In a sewing machine the combination of looper mechanism including a looper and means for actuating it, a loop retainer having a loop engaging end and a stem extending therefrom in a direction away from and in front of the loop engaging end of the looper and pivotally supported to permit its loop engaging end to swing transversely of the main direction of movement of the looper, a cam for swinging said loop retainer, said cam having a concentric face throughout the major part thereof and an eccentric face for a small part thereof having a gradual easy curve uniting such faces, and means for adjusting the loop retainer.

30. In a sewing machine the combination of looper mechanism including a looper and means for actuating it, a loop retainer having a loop engaging end and a curved stem extending downwardly therefrom in a direction away from and to the front of the loop engaging end of the looper and pivotally supported to permit its loop engaging end to swlng transversely of the looper, and

means for swinging said loop retainer.

31. In a sewing machine the combination of stitching mechanism includinga needle and a looper, actuating means therefor, a pivotally supported loop retainer, and means for swinging it in a horizontal plane to retain the needleloop while the needle is descending and for withdrawing the retainer into its initial position as soon as the needle has secured the loop of the looper thread.

32. In a sewing machine the combination of stitching mechanism including a needle and a looper, actuating means therefor, a pivotally supported loop retainer, and means for swinging it in a horizontal plane to re tain the needle loop while the needle is descending and for withdrawing the retainer into its initial position as soon as the needle has secured the loop of the looper thread, said swinging means comprising a cam.

In a sewing'machine the combination of stitching mechanism including a needle and a looper, actuating means therefor, a pivotally supported loop retainer, and means for-swinging itin a horizontal plane to'retain the needle loop while the needle is de seending and for withdrawing the retainer into its initial position as soon as the needle has secured the loop of the looper thread, said swinging means comprising a cam having a concentric portion throughout the major part thereof and an eccentric part for a small portion thereof having a gradual easy curve uniting such portions.

34. In a sewing machine the combination of stitchingmechanism including a needle and a looper, actuating means therefor, a pivot-ally supported loop retainer, means for swinging it in a horizontal plane to retain the needle loop while the needle is descending and for Withdrawing the retainer into its initial position as soon as the needle has secured the loop of the looper thread, said swinging means comprising a cam having a concentric portion throughout, the major part thereof and an eccentric :part for a small portion thereof having a gradual easy curve uniting such portions, and spring actuated means for holding the retainer in engagement with the cam.

35. In a sewing machine the combination of stitching mechanism including a needle and a looper, actuating means therefor, a pivotally supported loop retainer, means for swinging it in a horizontal plane to retain the needle loop while the needle is descending and for withdrawing the retainer into its initial position as soon as the needle has secured the loop of the looper threadgsaid swinging means comprising a cam, and spring actuated means for holding the retainer in engagement with the cam.

36. In a sewing machine having-looper mechanism including a looper, of a pair of needle guards connected :with the looper mechanism,-one having a variable movement relatively to the looper blade and the other having a fixed position relatively-thereto but havin a movement with the looper blade in diiferent directions.

Signed at Philadelphia, in the county'of Philadelphia and State of Pennsylvania, this 8 day of January, 1916.

HARRY J. DAHL.

lVitnesses:

J. RUSSELL IVINDER. DAVID L. Booos.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

